Execution starts in the main function (main is just a normal function).

A function must be declared before it is used:
This means either the entire function has to be located before any calls
to it or you have to add a function declaration for it (preferably at
the top of the file). A function declaration is just the header part
with a semicolon at the end.

The init commands are evaluated just once, usually to initialize variables.
Then the condition is evaluated - if it is false, the statement terminates,
and if it is true, the statement executes. After that, the per loop commands
are executed and the loop starts over.

For example:

for( t = 0; t < endtime; t++ )
{
i += t;
}

if/else
This loop executes a block of commands if the condition is true. If false
it executes the block of commands after the else (else part is optional).

Format:

if ( condition )
{
commands
}
else
{
}

For Example:

if ( sky_color == 1 )
{
new_color = 2;
}
else
{
new_color = 1;
}

return
Returns from the current function/thread and optionally returns a value.